Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

2. During the following winter all Hellas was stirred by the great overthrow of the Athenians¹ in Sicily. The states which had been neutral determined that the time had come when, invited or not, they could no longer stand aloof from the war; they must of their own accord attack the Athenians. They considered, one and all, that if the Sicilian expedition had succeeded, they would sooner or later have been attacked by them. The war would not last long, and they might as well share in the glory of it. The Lacedaemonian allies, animated by a common feeling, were more eager than ever to make a speedy end of their great hardships. [2] But none showed greater alacrity than the subjects of the Athenians, who were everywhere willing even beyond their power to revolt; for they judged by their excited feelings², and would not admit a possibility that the Athenians could survive another summer. [3] To the Lacedaemonians themselves all this was most encouraging; and they had in addition the prospect that their allies from Sicily would join them at the beginning of spring with a large force of ships as well as men; necessity having at last compelled them to become a naval power. [4] Everything looked hopeful, and they determined to strike promptly and vigorously. They considered that by the successful termination of the war they would be finally delivered from dangers such as would have surrounded them if the Athenians had become masters of Sicily³. Athens once overthrown, they might assure to themselves the undisputed leadership of all Hellas.